Conventionally, electrostatic dust collectors for use in the atmosphere have been widely used in various technical fields. However, no apparatus for removing dust in a vacuum environment has been proposed. Thus, in the case where gas, etc. are fed into a vacuum environment, at most a filter has been employed so as to minimize entry of dust into the vacuum environment. In this case, the filter can achieve a rather excellent dust collecting effect. However, the filter cannot remove dust generated from an exhaust pump operated in a vacuum environment, such as an ion pump, a titanium sublimation pump, etc. nor can it remove a thin layer of dust adhering to a wall of a vacuum chamber. Thus, wafers of the semiconductors, the apparatus for producing the wafers, etc. are soiled with dust generated in the vacuum environment. Hence, yield of the wafers, etc. falls and the exhaust pump also deteriorates. Meanwhile, dust is collected in the high-frequency accelerating chamber of the particle accelerator. Thus, if dust adheres to high pressure components of the particle accelerator, abnormal electric discharge happens, thereby resulting in insufficient acceleration of particles.
Meanwhile, in the known electrostatic dust collectors for use in the atmosphere, air or gas is passed between collecting electrodes such that dust in the air or gas is caused to adhere to the collecting electrodes. Hence, the known electrostatic dust collectors cannot be used for removing dust adhering to the wall of the vacuum chamber or the wafers. In addition, even if dust is caused to adhere to the collecting electrodes, dust falls therefrom when the electric charge of dust vanishes, so that cleaning in the vacuum environment cannot be performed by the known electrostatic dust collectors.